https://djbouncemix.com/blog/wp-content/plugins/a-gallery/js/a-gallery.js?ver=5.1.19

1var leftCount = [];
2var rightCount = [];
3var itemCWidth = [];
4
5jQuery( document ).ready( function( $ ) {
6	$( ".a-gallery-left" ).click( function() {
7		postId = $( this ).parent().attr( "rel" );
8		if ( leftCount[ postId ] > 0 ) {
9			$( this ).parent().children( ".a-gallery-container" ).children( ".slider" ).animate( {"left": "+=" + itemCWidth[ postId ] + "px" }, "normal");
10			rightCount[ postId ] = rightCount[ postId ] + 1;
11			leftCount[ postId ] = leftCount[ postId ] - 1;
12		}
13	});
14	
15	$( ".a-gallery-right" ).click( function() {
16		postId = $( this ).parent().attr( "rel" );
17		if ( rightCount[ postId ] > 0) {
18			$( this ).parent().children( ".a-gallery-container" ).children( ".slider" ).animate( {"left": "-=" + itemCWidth[ postId ] + "px"}, "normal");
19			rightCount[ postId ] = rightCount[ postId ] - 1;
20			leftCount[ postId ] = leftCount[ postId ] + 1;
21		}
22	});
23});